A Novel Metastable Pentavalent Plutonium Solid Phase on the Pathway from Aqueous Plutonium(VI) to PuO(2) Nanoparticles

Here we provide evidence that the formation of PuO(2) nanoparticles from oxidized Pu(VI) under alkaline conditions proceeds through the formation of an intermediate Pu(V) solid phase, similar to NH(4) PuO(2) CO(3) , which is stable over a period of several months. For the first time, state-of-the-art experiments at Pu M(4) and at L(3) absorption edges combined with theoretical calculations unambiguously allow to determine the oxidation state and the local structure of this intermediate phase.